This essay offers a new interpretation of Aristotle’s remarks on how music affects the character of its listeners (Pol. VIII 5, 1340a14-b5). I will argue that these remarks appear less cryptic if we remember that Aristotle’s conception of moral virtue regards emotions not just as motivational forces (which help or hinder us from doing the right things) but as constitutive of virtuous behaviour itself. The main advantage of this approach to Polities VIII 5 is that it fits the dialectical setting of the text, which is marked by a disagreement over the powers of music and by the attempt to rely on empirical observations. [http://www.degruyter.com/view/j/apeiron.2013.46.issue-4/apeiron-2013-0020/apeiron-2013-0020.xml]